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<a name="boost.function_base"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle">Class function_base</span></h2>
<p>boost::function_base — The common base class for all Boost.Function
    objects. Objects of type function_base may not be created
    directly.</p>
</div>
<h2 class="refsynopsisdiv-title">Synopsis</h2>
<div class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../function/reference.html#header.boost.function_hpp" title="Header &lt;boost/function.hpp&gt;">boost/function.hpp</a>&gt;

</span>
<span class="keyword">class</span> <a class="link" href="function_base.html" title="Class function_base">function_base</a> <span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>

  <span class="comment">// <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_2-bb">capacity</a></span>
  <span class="keyword">bool</span> <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_2_1-bb"><span class="identifier">empty</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>

  <span class="comment">// <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_3-bb">target access</a></span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> <span class="identifier">Functor</span><span class="special">*</span> <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_3_1_1-bb"><span class="identifier">target</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> <span class="keyword">const</span> <span class="identifier">Functor</span><span class="special">*</span> <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_3_1_2-bb"><span class="identifier">target</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> <span class="keyword">bool</span> <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_3_2-bb"><span class="identifier">contains</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Functor</span><span class="special">&amp;</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">type_info</span><span class="special">&amp;</span> <a class="link" href="function_base.html#id-1_3_15_6_2_1_2_3_3-bb"><span class="identifier">target_type</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.15.6.3.4.4"></a><h2>Description</h2>
<div class="refsect2">
<a name="id-1.3.15.6.3.4.4.2"></a><h3>
<a name="id-1_3_15_6_2_1_2_2-bb"></a><code class="computeroutput">function_base</code> capacity</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_15_6_2_1_2_2_1-bb"></a><span class="identifier">empty</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
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<td><p><span class="term">Returns:</span></p></td>
<td>
<code class="computeroutput">false</code> if <code class="computeroutput">this</code> has a target, and <code class="computeroutput">true</code> otherwise.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Will not throw.</td>
</tr>
</tbody>
</table></div>
</li></ol></div>
</div>
<div class="refsect2">
<a name="id-1.3.15.6.3.4.4.3"></a><h3>
<a name="id-1_3_15_6_2_1_2_3-bb"></a><code class="computeroutput">function_base</code> target access</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><a name="id-1_3_15_6_2_1_2_3_1-bb"></a><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> <span class="identifier">Functor</span><span class="special">*</span> <a name="id-1_3_15_6_2_1_2_3_1_1-bb"></a><span class="identifier">target</span><span class="special">(</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> <span class="keyword">const</span> <span class="identifier">Functor</span><span class="special">*</span> <a name="id-1_3_15_6_2_1_2_3_1_2-bb"></a><span class="identifier">target</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
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<td><p><span class="term">Returns:</span></p></td>
<td>If <code class="computeroutput">this</code> stores a target of type
        <code class="computeroutput">Functor</code>, returns the address of the
        target. Otherwise, returns the NULL
        pointer.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Will not throw.</td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> <span class="keyword">bool</span> <a name="id-1_3_15_6_2_1_2_3_2-bb"></a><span class="identifier">contains</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Functor</span><span class="special">&amp;</span> f<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
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<td><p><span class="term">Returns:</span></p></td>
<td>
<code class="computeroutput">true</code> if <code class="computeroutput">this-&gt;<a class="link" href="function_base.html#id-1_3_15_6_2_1_2_3_1-bb">target</a>&lt;Functor&gt;()</code> is non-NULL and <code class="computeroutput"><a class="link" href="function_equal.html" title="Function template function_equal">function_equal</a>(*(this-&gt;target&lt;Functor&gt;()), f)</code>
</td>
</tr></tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">type_info</span><span class="special">&amp;</span> <a name="id-1_3_15_6_2_1_2_3_3-bb"></a><span class="identifier">target_type</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
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<td><p><span class="term">Returns:</span></p></td>
<td>
<code class="computeroutput">typeid</code> of the target function object, or <code class="computeroutput">typeid(void)</code> if <code class="computeroutput">this-&gt;<a class="link" href="function_base.html#id-1_3_15_6_2_1_2_2_1-bb">empty</a>()</code>. Works even with RTTI off.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Will not throw.</td>
</tr>
</tbody>
</table></div>
</li>
</ol></div>
</div>
</div>
</div>
<div class="copyright-footer">Copyright © 2001-2004 Douglas Gregor<p>Use, modification and distribution is subject to the Boost
    Software License, Version 1.0. (See accompanying file
    <code class="filename">LICENSE_1_0.txt</code> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</p>
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